The results of our work provide evidence that the amount of food consumed during suckling plays an important role in determining the habitual food intake of rats in later life. Further, by controlling the food intake of the newborn rat, it is actually possible to "program" the animal for a desired voluntary food intake in later life. These results might constitute an important element in the final elucidation of the overall development of a variety of metabolic abnormalities associated with excessive caloric intake such as obesity. In a separate experiment, the effects of one bout of work on intracellular free fatty acids (FFA) of adipose tissue were examined. Surprisingly, FFA were elevated in epididymal, inguinal and retroperitoneal depots 48 hrs (but not 96 hrs) after a 2 hr swim in previously untrained rats. These results provide evidence that the rise in FFA is an acute effect of exercise and not a cellular adaptation resulting from daily episodes of lipolysis induced by exercise-training.